The present invention relates generally to frequency synthesizers, and more particularly to a phase-locked loop frequency synthesizer which can be switched to any of a group of communication channels.
A PLL frequency synthesizer having a charge pump is known. If this type of synthesizer is used for communication channels, and a switching occurs between channels, the synthesizer needs a long period of time to lock its frequency with the new channel. This occurs when the frequencies of these channels are close to each other.